1. Field of Invention
The present invention relates generally to the field of mobile communication devices. More specifically, the present invention is related to anonymously testing proximity between mobile users without revealing individual phase space coordinates.
2. Discussion of Prior Art
Application Service Providers (ASP""s) are increasingly offering a myriad of services over various networks. Many of these services make use of a user""s location data to provide targeted user-specific information.
A specific implementation of such a service is a location-based service that requires detecting and reporting the relative proximity of two or more users. There exists a multitude of Wireless Service Providers (WSPs) that are able to deliver Location Tracking Services (LTSs) (or they may allow users to subscribe to a multitude of such LTSs). Since individuals may wish or need to be aware of their proximity to users subscribing to different service providers, information must be exchanged between the different service providers to detect proximity. Exchanging an individual""s location data is undesirable, as it exposes the user to potential threats with regard to his/her privacy. By the same token, not exchanging the data severely diminishes the utility of such location-based services.
A brief description of prior art in the area of location-based services is provided below, but it should be noted that the prior art fail to provide for a system or method to anonymously test for the proximity of users without exchanging their location coordinates.
A prior art solution concerning the exchange of a user""s location data involves encrypting the location data and sharing such encrypted data between the wireless service providers. This solution, however, has some major disadvantages, some of which are outlined below:
1) Management of the public key encryption is complexxe2x80x94especially given the rate of queries and proximity calculations required. An individual wireless provider may have millions of clients, and each of these clients may wish to be alerted to the proximity of users of dozens of other wireless services.
2) Assuming the wireless providers exchange the information protected by encryptions, at some point the other service providers will be in possession of the location data for non-subscribing users. This requires that users trust every wireless provider (whether they are subscribers or not) to control access to this data. The system and method of the present invention eliminates this problem by avoiding the sharing of sensitive data.
The published patent application to Doi et al. (US 2001/0014911 A1) provides for a method and system for providing services wherein a trusted service provider provides service information dependent on location information of a mobile terminal to the mobile terminal in response to a service request with the location information sent by the mobile terminal. Doi et al., however, fail to address privacy concerns in the communication between multiple instances of such services.
The published patent application to Kinnunen et al. (US 2001/0018349 A1) provides for location-dependent services. Disclosed is a location-based system (LBS) for providing location-dependent services to a plurality of mobile terminals within a coverage area.
The published patent application to Watson (US 2002/0026517 A1) enables communications of electronic data between an information requestor and a geographically proximate service provider. Disclosed is a method for transferring electronic data comprising: receiving a request to access a communications system at a first geographical location from a client located at a second geographical remote from the first geographical location; identifying a proxy local to the client in the second geographical location; and receiving subsequent data requests from the client at the proxy. Watson, however, fails to disclose a third-party anonymous function evaluation service. Additionally, Watson requires trust and knowledge between the service providers.
The PCT publication to Huber et al. (WO 0079811 A2) provides for a method and system for offering mobile subscribers anonymous, location-based services. Disclosed is a method wherein a user, who has his/her own trusted service provider, picks one or more services he/she is interested in and sends his/her location to the trusted service provider, whereupon the service provider gets the location of the service and performs a range query. Thus, the service provider researches locations for services (for example, the yellow pages). The PCT publication to Lammi et al. (WO 0128273 A1) provides for a similar recitation.
The published patent application to Hunzinger (US 2002/001173 A1) provides for communication of location information in a wireless communication system. Disclosed is a mobile station, such as a cellular or PCS phone, in a wireless communication system which transmits position information to the system server. The mobile station may communicate position location and movement tracking information between the mobile station and the wireless communication infrastructure.
The U.S. patent to Drane et al. (U.S. Pat. No. 6,275,705) provides for a location tracking system. The method allows for finding the position of a mobile radio-frequency transceiver in a communications system. Determination includes the means to use the known distances and measured times to determine the relative time offsets of transmissions from each base station and location means to use the determined relative time offsets and to calculate the position of a mobile transceiver in the network area using hyperbolic positioning techniques.
The PCT publication to Natarajan et al. (WO 01/65339) provides for an architecture for providing information to devices wherein the architecture comprises a data collector, an information server, an evaluation mechanism, and an action handler. The evaluation mechanism determines if a change occurs in an evaluation of an expression and generates a notification.
The non-patent literature to Herzberg et al. entitled xe2x80x9cOn Traveling Incognitoxe2x80x9d discusses solutions to anonymity in mobile environments. A xe2x80x9cfrequently changingxe2x80x9d aliasing is provided as part of the solution.
Whatever the precise merits, features, and advantages of the above-cited prior art, none of them achieves or fulfills the purposes of the present invention.
The present invention provides for a system and a method for anonymizing data associated with mobile telephone users in a phase space, wherein such data is used in the calculating proximity between the users without divulging their location or preference vectors in the phase space. The privacy is kept by providing location coordinate information or preference vector coordinate information in steps, along with an evaluation function. The services receive the partial results and then locally compute the final result, giving a proximity estimate. It should be noted that the term proximity includes not just proximity in terms of Euclidean distance but includes proximity in a phase space made of preference profiles and vectors (e.g., affinity for baseball, apple pie, ballroom dancing, etc.).
In a specific embodiment, the present invention""s method assists a first and second location tracking service (LTS) in anonymizing location data associated with a first and second user in a phase space, wherein the first and second user are tracked by the first and second LTS respectively. The location data is defined by one or more parameters. The method, as implemented in an anonymous function evaluation service (AFES), comprises the following steps: (1) receiving a request for function evaluation from each LTS, wherein the request identifies a parameter to be transmitted and a corresponding function to be used for evaluating said identified parameter; (2) transmitting a confirmation to each LTS indicating the AFES is awaiting reception of the identified parameter; (3) receiving the identified parameter from each LTS; (4) evaluating the corresponding function based on the received parameter from each LTS; and (5) transmitting the evaluated result to each LTS. Steps a-e are repeated for each additional parameter required to define location data and corresponding function such that each of said LTS""s receives function evaluated results from said AFES for each parameter separately and utilizes such evaluated results to locally estimate proximity between said first and second user in said phase space without revealing their location data.
The anonymous function evaluation service (AFES) of the present invention comprises: (1) an interface to communicate with various location tracking services (LTSs) or wireless service providers (WSPs) and receive parameters and corresponding functions; (2) a task list storing the functions to be evaluated on received data; (3) a data cache storing the received parameters to be processed; (4) a function evaluation engine evaluating mathematical function(s) on parameters; and (5) a task manager operatively linked with the task list, data cache, and function evaluation engine, said task manager: receiving parameters and corresponding functions from the interface; sending the functions and parameters to task list and data cache respectively; retrieving said functions from data cache; and communicating with function evaluation engine and sending results of the function evaluation engine back to the interface for forwarding values to requesting services.